Captive aircraft control



Oct. 9, 1951 w, H, BURKS, JR 2,570,316

CAPTIVE AIRCRAFT CONTROL Filed oct. 11, 1949 2 sheets-sheet 1 F/G. l.

46 Z7 zg oct. 9, 1951 w'. H. BURKS, JR 2,570,316

CAPTIVE AIRCRAFT CONTROL Filed Oct. 11, 1949 2 Sheets-Sheet 2 FIC-. 2.

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3 slide 20 is suiciently advanced in an inboard direction to take the pin 31 out of the slide bar hole 36. timer arm 8 and engine carburetion adjusted to produce the R.. P. M. desired for flight. The timer arm 8 is then retarded to idling position so that the pin 31 is reengaged with the hole 36 in the slide bar 3| and the timer is held in idling position, in which the engine 1 idles and the airplane remains in stationary position on the ground or other flight platform. The operator then takes his position at the remote end of the control wires 39, 40 and by giving these wires a brisk pull the slide 29 is moved in an inboard direction against the resistance of the spring 28 and the pin 31 is disengaged from the slide bar hole 36 and the spring 32 advances the slide bar 3| and hence the timer arm 8 to flying The engine 1 is then started and the `V2,570,316 `f i speed position, so thatthe engine 1 drives the propeller 4| at the predetermined ight speed and produces a take-off of the airplane 5. The operator uses the wires 39 and 40 to control the airplane 5 for take-off, flight, and for landing. This eliminates the need for a second person to hold the airplane while the operator takes his control position, and to release the airplane upon a signal from the operator, as is the usual procedure. Y

A spacer 42 rising from a forward central part of the slide has mounted on its upper end a T-shaped master bell crank 43 by means of a bolt 44 passing through the middle of the crosshead 45 of this bell crank. The arm 46 extends in an inboard direction from the middle of the cross-head 45 and is formed with a longitudinal slot 41. Along one side of the slot 41 is a series of holes 48. The inboard end of the retarding and tensioning spring 28 is connected to the spacer 42.

A pivot 49 on the rear side of the base plate I1 in line with the spacer 42 in the retracted position of the operating slide 29, as shown in Figure 2, mounts a T-shaped rudder bell crank 50, the pivot 49 passing through the middle of the cross-head 5|. A right-angularrarm 52 extends forwardly from the cross-head 5| and has a longitudinal slot 53 sldably engaging the spacer 42, so that whenever the operating slide 26 is moved, the rudder bell crank 50 is swung on its pivot 49. On each side of the pivot 49 the cross-head 5| has a series of holes 54. The middle portion of the master bell crank 43 is de'- pressed, as shown in Figure 3.

Lugs 55 rise from the front and rear, edges of the base plate I1 in line with the inboard end of the arm 46 of the master bell crank 43 and slidably support an elongated elevator actuator bar 56. The bar 56 includes upper and lower rods 51 and 58, respectively, between whose middle points a pin 59 is carried which slidably engages the slot 41 of the arm 46 of the master bell crank 43, with the arm 46 between the rods. The rearward end of the rudder actuator bar 56 is'provided with a hole 69.

As shown in Figure 1, the operators control wires 39 and 4|] are connected to the opposite ends of the cross-head 45 of the master bell crank 43 and pass through guides 6I and 62, respectively, on the left or inboard wing tip.

Each of the wing flaps I4 is operated by a connection 63 between its horn I4' and one arm of a bell crank 64 mounted on the related wing, having the other arm thereof connected by a wire 65 with the rearward hole 23 in the outboard slide guide 22.

Each of the ailerons I5 is connected by a connection 66 with one arm of a bell crank 61 mounted forwardly on the related wing, the other arm of the bell crank 61 being connected by a wire 68 with the forward end of the lower slide guide 22. The bell cranks 61 are reversed with respect to each other so that in the true preflight disposition of the airplane, shown in Figure l, the right wing aileron I5 is angled in up position and the left wing aileron I4 is angled in down position, as shown in full lines. The initial amount of such angulations is determined by -of the cross-head 5| of the rudder bell crank 50,

the connections being niade in selected ones of the holes 54.

The reason the control horns |44 and I5 of the flaps and ailerons are on the under sides thereof is that when the centrifugal pull is greater than the slide-retarding spring 28, the slide 20 is pulled toward the left or inboard side of the airplane. With this motion wire 68 connected to bell crank 61 relays the pull to the aileron I5 through wire 66. To cause the aileron I5 on the right wing to move from full up to an intermediate position, the pull must be applied to the under Side of the aileron. Therefore, the control horns I4 and I5' must be on the under sides of the control surfaces.

As viewed in Figurefl, the positions of the control surfaces preceding flight are:

Aileron on right Wing I3 at up position;

Aileron on left Wing I2 at down position;

Rudder 9 at full right position;

Flaps I4 at down position;

Elevators I0 and I I at positions desired by operatOr.

When the airplane 5 takes 01T, the ailerons I5, which are coordinated with the rudder 9, cause the airplane to make a right turn and Vbank so as to keep the control wires 39 and 40 taut, the amounts of turn and bank being limited by the pull on the control wires. As the airplane gains speed and its centrifugal pull on the control wires increases, the operating slide 20 is pulled away from its retracted position. As a result, the ailerons I5 are moved past an intermediate position or to a position determined by the operator. At the same time, the flaps I4 are moved toward up position. When the motor runs out of gas, the speed of the plane diminishes and the centrifugal pull on the control Vwires 39 and 4U being lessened, the spring 28 returns the operating slide 20 to retracted position, thereby throwing the aps VI4 down to landing position.

During the actions described above, the rudder 9 is turned away from full rudder position toward an intermediate'position or one determined by the operator, since, as the speed of the airplane 5 increases, less rudder is needed. As the speed of the airplane decreases and the pull on the wires 39 and 40 lessens, the retracting movement of the operating slide 20 restores the rudder 9 toward full rudder position. Y

The left elevator Il] moves up when the front control Wire 39 is pulled and down when the rear control wire 40 is pulled or tightened. More elevator is required at slow speed than athigh speed, and this is provided for by the leverage-reducing pin-and-slot connection of the master bell 453 with' the elevatoractuatrfbarf, 'whereby over-controlling fthe'eleVa-tOr #-I dis-precluded. lA'taut conditionf'ofthe control -Wires `3V91and ill'is necessary'tofullcontrl-fat'all times of the airplane -5. Whenever the "airplane is caused, as by ahstrongwindto vdeviate from -`its=es"tab lished -path and Lmove toward' the operator land -produce slack-in thecontr'ol wires-the rspring-Z 8 isf freed to returnthe operating-slide-2iltofre Atracted, initial position, `thereby'returningfthe ailerons, flaps, rudder and elevator Y'to their :initial positions; and therebyfcausing thelairplane 5 -to return to its established i-flight"path *or course, wherein the"-jcontrol Wires139 and Elli-bepmetaut. f Y "'To-cause the-airplane to'laseend, the-front wire Sil-is pulled-` bythe operator. vWith theairplane' in'ilight, the 'rear 'wire 450 -isg pulled 'toJ cause 'theiairplane todescen'd'. Y

The holes-48 are provided-in-thearrn1S yofi-the mas-ter `bell crank 43 toienableconnection of feletraitor-linkage sor as to eliminate "variable 7changes 'in-leverage to the-elevatorswhen "constant full travel of the elevator is needed for stuntingfthe airplane. -Such connection` does not change the action of the control unit I6 in controlling the rudder, ailerons, flaps, landing-gear or any other fcontrolelement: that is Aactuated byv Lth'eopera'ting slide 2U. l

The above-describedl device aids jin, preventing the airplane from slipping toward the operator when at the maximum altitude of the `control ilines. Further, captive airplanes made longer and heavier than 'now practical maybe hand owniwhen equipped-with' thisgdevice. j j

^ IIt Lwill "therefore "be understood that to 'begin the counterclockwise `flight of :the airplane, 'the control surfaces are pre-set so as to cause the airplane 5 to have a tendency to execute a right turn and bank. The pre-set position of the controls should be so as to have the aileron on the right or outboard wing to be at up position. The aileron on the left or inboard wing should be at down position. This causes the airplane to have a tendency to execute a right bank away from the operator, thus keeping the control wires taut.

The rudder 9 is pre-set to full right position, and since the ailerons and rudder are coordinated, the airplane tends to execute a right turn and bank away fromV the operator. This right turn and bank is limited by the pull on the control wires. As the airplane overcomes static inertia and gains flying speed, the centrifugal pull increases and at maximum speed the pull is intensied and may build up to a point greater than the operator can safely hold. The centrifugal pull is relieved at the point that the centrifugal pull becomes greater than the tension of the slide-retarding spring 28. At that point the slide is pulled toward the inboard or left side of the plane and by linkage to the ailerons and rudder they are caused to move to an intermediate or neutral position.

Should the centrifugal pull at that time be greater than the operator can safely hold, then on the next flight the ailerons and rudder can be pre-set to move past the intermediate or neutral position, thus further relieving the centrifugal pull. This adjustment must be made to fit the flight characteristics and weight of the airplane. As the engine stops and the airplane slows up to landing speed, then more control is needed to keep the wires taut at sloW speed.

This is achieved when the centrifugal pull becomes less than that of the slide-tensioning spring# Z8.'Atlsuchpointfthe-spring 23 pullsthe slide toward the right or Youtboard'side of 'the piane'and movesthe--aileronJ on the/'right wing toupposition,theaileron on `the left oroutboard -wingtoy down position,VV and moves rudder`9fback1to full right position. 1 'Thisltendsitohold=the1plane against fthe control wires, `thereby `keeping them taut.

`LWhatis-:claimed is: n

"'1. In 'a ycaptive l airplane `having i Wing flaps, ailerons, `a rudder, van elevator, and a fpair of operators control wires extending laway from the inboard sidef of Ithe l airplane, la control unit comprising'a base Vmounted -stationarilyon the airplane,an operating sl-ide mounted on said-base for vmovement `crossw-ise of vthe Vairplane 'in .inboard and outboard directions, retractingspring mea-ns 4Vfor-returning lsaid operating slide in ian outboard direction opposite tothe pullof the Voperator-"s control Wires, -amaster bell crank pivoted intermediateitsends on saidoperating slide v:havingsa'id `operators' control Wires severally connected to `opposite ends vthereof whereby Va :greater pull on V'one 'ofv said controlwires pivots said-master bell'crank out of'an `intermediate position and into aJflight-'correcting'position, a

rudder bell crank 'pivoted on "saidbase plate at one side' of Asai'd'rnaster bell crank and having a pin-and-slot vconnection "with said 'master bell crank `and operating slide, `an elevator ractuator bar mounted on said base plate to slide'end- Ywise across said operatingislide Vand Vhaving ,Ta

j necting` said elevatoriactua'tor barwith said velevator, and lfourth" means'connecting said operating slide with said ailerons, said rudder, saidV flaps, and said ailerons being initially set for a predetermined centrifugal night path for the airplane relative to a position of the operator with said operating slide in retracted position, Whereby when the centrifugal pull upon said operators control wires becomes greater or less as said airplane moves in said predetermined flight path and its speed of flight therein increases or decreases, said operating slide will be progressively pulled away from its retracted position against the resistance of said spring means or permitted to be retracted by said spring means so as to coordinately produce corresponding corrective positionings of saidrudder, said elevator, and said ailerons for the increase or decrease in speed, and whereby whenever said airplane is forced out of the predetermined flight path toward the operators position and said control wires tend to become slack, said spring means will act to retract said operating slide to its retracted position and thereby restore the initial setting of said rudder, said flaps and said ailerons so as to maintain the airplane in its predetermined flight path and maintain the control wires taut.

2. In a captive airplane having wing flaps, ailerons, a rudder, an elevator, and a pair of operators control wires extending away from the inboard side of the airplane, a control unit comprising a base mounted stationarily on the airplane, an operating slide mounted on said base for movement crosswise of the airplane in inboard and outboard directions, retracting spring means for returning said operating slide in an outboard direction opposite to the pull of the operators control Wires, a master bell crank pivoted inter- 7 mediate its ends on said operating Vslide having said operators control Wires severally connected to opposite ends thereof whereby a greater pull on one of said control wires pivots said master bell crank out of an intermediate position and into a flight-correcting position, a rudder4 bell crank pivoted on said base plate at onevside of said master bell crank and having a pin-and-slot connection with said master bell crank and operating slide, an elevator actuator bar mounted on said base plate to slide endwise across said operating slide and having a pin-and-slot connection with said master bell crank, rst means connecting said rudder bell crank with said rudder, second means connecting said slide with said flaps, third means connecting said elevator actuator bar with said elevator, and fourth means connecting said operating slide with said ailerons, said rudder, said aps, and said ailerons being initially set for a predetermined centrifugal flight path for the airplane relative to a position of the operator with said operating slide in retracted position, whereby when the centrifugal pull on said operators control wires becomes greater or less as said airplane moves in said predetermined flight path and its speed of flight therein increases or decreases, the operating slide will be progressively pulled away from its retracted position against the resistance of said spring means or permitted to be retracted by said spring means so as to coordinately produce corresponding corrective positionings of said rudder, said elevator, and said ailerons for the increase or decrease in speed, and whereby whenever said airplane is forced out of the predetermined iiight path toward the operators position and said control wires tend to become slack, said spring means will act to retract said operating slide to its reytracted 'position and thereby restore the initial setting of said rudder, said flaps, and said ailerons so as to maintain the airplane in its predetermined ight path and maintain the control wires taut, said airplane having antengine timer arm, an engine timer control slide bar mounted on said base plate for endwise movement adjacent said operating slide, spring means projecting said slide bar in a direction to produce advance of said timer arm, means connecting said slide bar with said timer arm whereby in the projected position of said slide barvsaid timer arm is in advanced position for night speed operating of the associated engine, and means acting between said operating slide and said slide bar only in the retracted positions of said operating slide and slide bar whereby said slide bar and the connected timer arm are retained in engine-retarding position only while said operating slide is in retracted position and whereby said slide bar is moved by its spring means to projected position to advance said timer arm whenever said operating slide is pulled away from its retracted position. Y

WILLIAM I-I. BURKS, JR. Y

` REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date .i

2,061,953 Sampson Nov. 24, 1936 2,292,416 Walker Aug. 11, 1942 2,303,965 Walker Dec. 1, 1942 2,404,922 Padgett July 30, 1946 2,490,313 Meister Dec. 6, 1949 

